Portable power-operated saw

ABSTRACT

A portable power-operated saw comprising a blade with actuate teeth thereon which oscillates by means of a motor driving the blade and in which the output shaft of the motor rotates about an axis which cuts the axis about which the saw oscillates and the rotary motion of the motor is converted into the oscillating motion of the blade by a flat bladelike spring, one end of which is drivingly connected and parallel to the saw blade, while the other end of the spring is mounted by means of a spigot in a bearing on the output shaft of the motor and is eccentric therewith.

United States Patent,

30/(lnquired); 128/317, 310, 305, 92; 74/47 72 Inventor Arthur Kenneth Dabble [56] References Cited l N g, 521 England UNITED STATES PATENTS [211 APP 436,804 9/1890 Roberts l28/3 17x gai 1:2 3: 1,763,730 6/l930 VonLackum l28/3l7 t I 73 Assign Mum. Brothers Limited 3,365,963 l/ 1968 llappe.. 74/47 v 3 London, England i Primary Examiner-Donald R. Schran a British Company Anomey llolman, Glascock, Downing & Seebold [32] Priority Aug. 1 l, 1967 I p [33] Great Britain 37000/57- ABSTRACT: A portable power-operated saw comprising a .blade with actuate teeth thereon which oscillates by means of 3 a motor driving the blade and in which the output shaft of the [54] PORTABLE POWER'OPERATED SAW motor rotates about an axis which cuts the axis about which 7 5 Claims 2 Drawing the saw oscillates and the rotary motion of the motor is con- [52] [1,5, (I 128/317, verted into the oscillating motion of the blade by a flat 143/69, 74/47 bladelike spring, one end of which is drivingly connected and [5 1] Int. Cl A6lb l7/l4 parallel to the saw blade, while the other end of the spring is Field of Search 143/69; mounted by meansof a spigot in a bearing on the output shaft of the motor and is eccentric therewith.

. I 1 "IE; PORTABLttPOWER-OPERA'I'ED SAW The invention relates to portable power operat'ed oscillating saws, and in particular to 'a bone saw-,in which the axis of rotation is at right angles to the spindle of the'motor driving the SaWt' The invention comprising a blade" with teeth thereon arranged in a segment of a circle, and which in use oscillates about the center of the circle, and a motor for driving the blade, characterized in that the output shaft of the motor rotates about an axis which intersects the axis about-which the saw oscillates, means being prooscillating motion ofthe blade, which means comprises a flat bladelike spring, one end of which is drivingly connectedto the saw blade while the other end of the spring is mounted, by means of a spigot, in a bearingon theoutput shaftof the motor, the bearing being eccentric therewith,j

The invention further consists in apower-operated saw as set forth in the preceding paragraph in which the saw blade and the first mentioned end of the spring are parallel to one another, while the axis of rotation of the spigot in the eccentric bearing passes through the, axisof rotation of the saw in the plane of the spring at its first mentioned end where drivingly connected to the saw. v 1

- shaft of the saw and the blade like spring are mounted ina casing which is detachable from the casing forthe motor.

The accompanying drawing shows, by way of example only, one embodiment of the invention in which: FIG. 1 is a side elevation having a partial cross section in the plane parallel to the saw blade; while 1- FIG. 2 is a side elevation having a partial cross section in a plane at right angles to the saw blade. j

The sawcomprises a cylindrical casing l which houses a motor, either electric or pneumatic,--the latter being preferred due to its freedom from shock hazard, and its freedom from V explosion hazard in the presence of flammable gas mixtures, and to its small size. The motor is operated by pressure upon a lever 2.

A saw blade 3, which has teeth directions of stroke, is mountedon a'detachable portion 4 which is fastened to the casing lby a screw thread 5 upon each. The saw blade 3 is drivingly attachedto a saw shaft 6, by

means of splines, and is held inposition'by a hexagon headed screw 7. The shaft 6 is mounted flexibly in a silicone rubber or other suitable flexible material 8 within a cylindrical recess inv I a nose 9 of the tool which ispart of portion 4, and is therefore free to rotate a limited extent in both directions. The shaft 6 is centered in the recessiin the nose 9 by means of a ball 10.

.Also drivingly attached to the Shafi 6 is a flat bladelike spring ll by means ofa' bush 12. Consequently, the saw 3 and the spring 11 can oscillate together about the axis'of rotation consists; in a portable power-operated saw 'vided for converting the rotary motion 'of the motor into the By reason of the high spee The axis of rotation of an outputshaft 13 passes through the axis of the shaft 6 in the plane of the spring ll where attached to the latter, and is provided with "a boss 14 which houses a needle roller race 15 in a bore which is eccentric with respect to-the axis of the shafl l3, and is inclined in relation thereto. Theaxis of the roller race 15 also passes through the axis of shaft 6 where the spring] 1 is attached thereto.

The lower-end of the spring 11 is provided with a hardened spigot, which engages in the roller race 15, and in consequence, as the shaft 13 of the motor rotates the spigot describes a conical path, and due to'the flexibility of the spring 11 in one plane, it imparts an oscillating motion to the saw shaft and saw. The race 15 and spigot r'nay,altematively, be of barrel shape or evenspherical, to allow freedom for hinging oftheshaft6. v

movement of the end of the s 1 at in re ct to the bearin d of oscili t ion of the saw lfiade and its short stroke it is able to cut anobject which .is but lightly held, as for example a bone during bone surgery.

Furthermore, due to the limited v are of movement of the saw, the amount of clearance required during use is negligible.

' It is to be understood that the above description is by way of example only, and that details for carrying the invention into effect may be varied without departing from the scope of the invention claimed.

lclaimz l. A portable power-operated saw having a blade with teeth,

thereon arranged in a segment of alcjrcle, which teeth in use oscillate about the center of the circle, and a motor for driving the blade, the improvement comprising an output shaft of the motor which rotates about an axis 'which'intersects the axis about which the saw oscillates; means for -converting the romeans of silicone rubber.

tary motion, of the motor into the oscillating motion of the blade, which means comprises a flat bladelike spring, one end of which is drivingly connected to thesaw blade by a shaft while the other end is mounted, by, means of a spigot, in a bearingeccentrically mounted-on the output shaft of the motor; said means for converting therotary motion into oscillating motion being contained in a casing having a noselike portion including a recess; and one end of the saw shaft being mounted for restricted rotational movement in said recess by 2. A power-operated saw as claimedin claim 1, in which the i saw blade and said one end of the spring are parallel to one another, while the axis of rotation of the spigot mounted in the eccentric bearing passes through'the axisof rotation ofthe arranged to cut in both saw where the spring is drivingly connected thereto.

3. A power-operated saw as claimed in claim I, in which the 5. A power-operated saw as clai ed in claim 1, in which said recess is cylindrical and contains a hall mounted on the axis of the cylinder between the end of the cylindrical recess and the end of the shaft to maintain the shaft coaxial with the cylindricalrecess. v a I t 

1. A portable power-operated saw having a blade with teeth thereon arranged in a segment of a circle, which teeth in use oscillate about the center of the circle, and a motor for driving the blade, the improvement comprising an output shaft of the motor which rotates about an axis which intersects the axis about which the saw oscillates; means for converting the rotary motion of the motor into the oscillating motion of the blade, which means comprises a flat bladelike spring, one end of which is drivingly connected to the saw blade by a shaft while the other end is mounted, by means of a spigot, in a bearing eccentrically mounted on the output shaft of the motor; said means for converting the rotary motion into oscillating motion being contained in a casing having a noselike portion including a recess; and one end of the saw shaft being mounted for restricted rotational movement in said recess by means of silicone rubber.
 2. A power-operated saw as claimed in claim 1, in which the saw blade and said one end of the spring are parallel to one another, while the axis of rotation of the spigot mounted in the eccentric bearing passes through the axis of rotation of the saw where the spring is drivingly connected thereto.
 3. A power-operated saw as claimed in claim 1, in which the saw blade is splined to the saw shaft which is at right angles to the driving shaft of the motor, and the axis of the motor shaft intersects the axis of the saw shaft.
 4. A power-operated saw as claimed in claim 3, wherein said casing is detachable from a casing for the motor.
 5. A power-operated saw as claimed in claim 1, in which said recess is cylindrical and contains a ball mounted on the axis of the cylinder between the end of the cylindrical recess and the end of the shaft to maintain the shaft coaxial with the cylindrical recess. 